Switch having two pairs of contacts, one pair being formed of material having higherresisttvity characteristic than the other pair



P 7, 1965 E. R. PRICE ETAL 3,205,332

SWITCH HAVING TWO PAIRS OF CONTACTS, ONE PAIR BEING FORMED OF MATERIAL HAVING HIGHER RESISTIVITY CHARACTERISTIC THAN THE OTHER PAIR Filed Aug. 15, 1963 FIG. 2

INVENTORS BERTRAM F BUTLER %%%E T :%%2 BY JERRY L. WHITCOMB ATTORNEYS United States Patent 3,205,332 TWO PAIRS OF CONTACTS, ONE PAIR BEING FORMED OF MATERIAL ISTIC THAN THE OTHER PAIR Everett R. Price, Escondido, Bertram F. Butler, Encinitas, Jerry L. Whitcomb, Cardiff, and John F. Prescott, Encinitas, Califl, assignors to Kinetics Corporation, Solana Beach, Calif., a corporation of California Filed Aug. 15, 1963, Ser. No. 302,392 7 Claims. (Cl. 200-166) The present invention relates to an electrical switch which is resistant to electric arc erosion.

Electric arc erosion can change the electrical operating characteristics and reduce the lifetime of a switch. Arc erosion becomes an increasingly difficult problem as higher and higher electric currents are interrupted by a switch.

In recent years there has been an increasing interest in small lightweight equipment for rockets and space vehicles. For a given electrical current, the problem of electric erosion increases as the size of the switch decreases.

The switch of the present invention comprises a pair of mating contacts, each having two distinct contacts which make electrical contact, one of the contacts of one taots. The contacts first making contact with one another are formed of a material which is resistant to electric arc erosion, for example tungsten. The contacts to subsequently make contact are formed of a material which has a low electrical resistivity, for example copper.

in order to accomplish sequential contacting, one of the two contacts which firs-t makes contact is resiliently displaceable relative to the contact of which it is a part.

Spring means are incorporated in the switch to provide forces to maintain contact pressures between the contacting surfaces.

Openings are provided for the passage of coolants, either liquids or gases, through the switch.

Other features and advantages of the present invention will be apparent from the following description, reference being made to the accompanying drawing wherein a preferred embodiment of the invention is illustrated.

in the drawing:

FIG. 1 is a fragmentary view of the invention;

FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.

Referring in detail to the drawing, the switch is shown as comprising two mating contacts, namely the plug 20 and the socket 22.

The mating contacts 20 and 22 each have two distinct contacts which make electrical contact, 24 and 26, and 28 and 30 respectively. Contacts 26 and 30 make electrical contact prior to sections 24 and 28 making contact.

Contacts 26 and 30 which are the first to contact one another are made of a material which is resistant to electric arc erosion, such as tungsten. Contacts 26 and 30 are replaceable since they are subject to are erosion. Contacts 24 and 28 which contact one another last are made of a material which has a low electrical resistivity such as copper.

To accomplish sequential contacting socket contact 22 is in the form of a cylindrical open top pocket which is resiliently displaceable relative to contact 22 of which they are parts. This resilient displacement is made possible hy the presence of a spring 34. Spring 34 is disposed within the pocket and is confined by the stop plate 36 which is secured to the main body 38 of contact. 22.

3,205,332 Patented Sept. 7, 1965 The main body 38 of contact 22 is slotted with slots 40 so as to divide the upper portion of the main body into spring tangs 42, and these tangs provide contact force between contact section 28 of contact 22 and contact section 24 of contact 20. The spring tangs 42 being resiliently di-splaceable in a direction laterally, and herein shown as radial-1y to the longitudinal axis of the switch.

The diameter portion 24, the maximum diameter of spring tangs 48, and the minimum diameter of spring by external forces, are such that 22 are fully engaged, there is contact force between contact portions 24 and 28 and between the snapper element 44 and the main body 38.

The switch is cooled by the passage of the gases through the cooling passages 50 and 52, when in the presence of a gaseous atmosphere. The switch is cooled by the passage of the liquid through the cooling passages 50 and 52, when in the presence of encompassing liquid.

The movement of the snapper element 44 in the direction parallel to the longitudinal axis of the switch, is limited by the stop plate 36 in one direction and by ridges forming shoulders 54 and 56, which shoulders are formed integrally with the main body 38 and the element 44 respectively.

While the form of embodiment herein shown and described constitutes a preferred form, it is to be understood that other forms may be adopted falling within the scope of the claims that iollow.

We claim:

1. An electrical switch comprising in combination:

(A) A plug includingzt (l) a contact formed of material having low elec- I trical resistivity,

(2) a second contact formed of material having higher resistance characteristic to are erosion relative to the material of the first mentioned contact, said second mentioned contact extending longitudinally outwardly beyond the first mentioned contact;

(B) asocket including:

(1) a contact forming a pocket for receiving the contacts of the plug, said contact of the socket being formed of material having low electrical resistivity,

(a) said contact having an inwardly extending and integrally formed shoulder,

(2) an element having spring tangs slid-ably guided by and longitudinally movable in the pocket of the first mentioned contact of the socket and forming a second contact, said second mentioned contact of the socket being formed of material having higher resistance characteristic to arc erosion relative to the material of the first mentioned contact of the socket,

(a) said element of the socket having an integrally formed and outwardly extending shoulder adapted to engage the first mentioned shoulder for retaining said latter contact in the pocket,

(3) and means normally biasing the second mentioned contact of the socket longitudinally and outwardly of the first mentioned contact of the socket;

(C) one of the two first mentioned contacts of the plug and socket having means associated therewith for biasing it laterally toward the other of said two contacts.

2. An electrical switch as defined in claim 1, characterized in that the respective first mentioned contacts of sociated with the first memtioned contact of the socket.

3. An electrical switch as defined in claim 1, characterized in that the respective first mentioned contacts of the plug and socket are formed of copper.

4. An electrical switch as defined in claim 1, characterized in that the respective first mentioned contacts of the plug and socket are formed of tungsten.

5. An electrical switch as defined in claim 1, characterized in that the respective first mentioned contacts of the plug and socket are formed of copper and the respective second mentioned contacts of the plug and socket are formed of tungsten.

6. An electrical switch as ized to include:

(D) one of the contacts of the socket having means associated therewith for biasing it laterally toward the other contact of the socket.

7. An electrical switch comprising in combination:

(A) aplug including:

(1) a contact formed of material having low electrical resistivity,

(2) a second contact formed of material having higher resistance characteristic to are erosion relative to the material of the first mentioned contact, said second mentioned contact extending longitudinally outwardly beyond the first mentioned contact;

(B) a socket including:

(1) a contact forming a pocket for receiving the contacts of the plug, said contact of the socket being formed of material having low electrical resistivity,

(a) said contact having an inwardly extending shoulder,

(2) a second contact slidably guided by and longitudinally movable in the pocket of the first mendefined in claim 1, charactertioned contact of the socket, said second mentioned contact of the socket being formed of material having higher resistance characteristic to ,arc erosion relative to the material of the first mentioned contact of the socket,

(a) said second mentioned contact of the socket having a shoulder adapted to engage the first mentioned shoulder for retaining said latter contact in position and including spring tangs in frictional engagement with the interior wall of the socket,

(3) and means normally biasing the second mentioned contact of the socket longitudinally and outwardly of the first mentioned contact of the socket;

((1) one of the two first mentioned contacts of the plug and socket having means associated therewith for biasing it laterally toward the other of said two contacts.

Reterences Cited by the Examiner UNITED STATES PATENTS 1,913,522 6/33 Thompson et al. 200-166 2,295,338 9/42 Ely 200-166 X 2,445,588 7/48 Skeats 200-146 2,455,998 12/48 Hoye 200-146 3,167,630 1/65 Alderman et a1 200-148 X FOREIGN PATENTS 526,635 3/31 Germany.

KATHLEEN H. CLAFFY, Primary Examiner. ROBERT K. SCI-IAEFER, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,205,332 September 7, 1965 Everett R. Price et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should-read as corrected below.

Column 1, line 21, before "erosion" insert arc column 2, line 8, before "portion" insert of line 23, before "element" insert snapper lines 69 to 71,

strike out "An electrical switch as defined in claim 1, characterized in that the respective first mentioned contacts of 'sociated with the first memtioned contact of the socket" and insert instead An electrical switch as defined in claim 1, characterized in that the means (C) for biasing laterally is associated with the first mentioned contact of the socket column 3, line 4, for "first" read second Signed and sealed this 29th day of March 1966..

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. AN ELECTRICAL SWITCH COMPRISING IN COMBINATION: (A) A PLUG INCLUDING: (1) A CONTACT FORMED OF MATERIAL HAVING LOW ELECTRICAL RESISTIVITY, (2) A SECOND CONTACT FORMED OF MATERIAL HAVING HIGHER RESISTANCE CHARACTERISTIC TO ARC EROSION RELATIVE TO THE MATERIAL OF THE FIRST MENTIONED CONTACT, SAID SECOND MENTIONED CONTACT EXTENDING LONGITUDINALLY OUTWARDLY BEYOND THE FIRST MENTIONED CONTACT; (B) A SOCKET INCLUDING: (1) A CONTACT FORMING A POCKET FOR RECEIVING THE CONTACTS OF THE PLUG, SAID CONTACT OF THE SOCKET BEING FORMED OF MATERIAL HAVING LOW ELECTRICAL RESISTIVITY, (A) SAID CONTACT HAVING AN INWARDLY EXTENDING AND INTEGRALLY FORMED SHOULDER, (2) AN ELEMENT HAVING SPRINGS TANGS SLIDABLY GUIDED BY AND LONGITUDINALLY MOVABLE IN THE POCKET OF THE FIRST MENTIONED CONTACT OF THE SOCKET AND FORMING A SECOND CONTACT, SAID SECOND MENTIONED CONTACT OF THE SOCKET BIENG FORMED OF MATERIAL HAVING HIGHER RESISTANCE CHARACTERISTIC TO ARC EROSION RELATIVE TO THE MATERIAL OF THE FIRST MENTIONED CONTACT OF THE SOCKET, (A) SAID ELEMENT OF THE SOCKET HAVING AN INTEGRALLY FORMED AND OUTWARDLY EXTENDING SHOULDER ADAPTED TO ENGAGE THE FIRST MENTIONED SHOULDER FOR RETAINING SAID LATTER CONTACT IN THE POCKET, (3) AND MEANS NORMALLY BIASING THE SECOND MENTIONED CONTACT OF THE SOCKET LONGITUINALLY AND OUTWARDLY OF THE FIRST MENTIONED CONTACT OF THE SOCKET; (C) ONE OF THE TWO FIRST MENTIONED CONTAINS OF THE PLUG AND SOCKET HAVING MEANS ASSOCIATED THEREWITH FOR BIASING IT LATERALLY TOWARD THE OTHER OF SAID TWO CONTACTS. 